Peak detector circuits can find widespread uses in communication systems, such as for amplitude stabilization in oscillators, level measurement, demodulation, automatic tuning, automatic gain control, and power amplifier envelope tracking. Signals encountered in high-frequency narrowband systems can include either unmodulated sinusoids (e.g., in the case of oscillators), or modulated signals using a sinusoidal carrier. Peak detectors operating with such signals face conflicting requirements of precision, speed, dynamic range, and power consumption, but existing circuit topologies have limitations. Ensuring accuracy at low input levels is challenging. U.S. Pat. No. 7,355,456 provides an example of a complicated circuit attempting mathematical corrections to improve detector slope, but not accuracy.